Underwater diving is an activity enjoyed as a hobby and engauged in as a necessity to perform underwater services. However, both amateurs and professionals are susceptible to poor judgment regarding the amount of their primary air/oxygen reserves, thus risking consumption of their primary air supply before they are able to surface. Also, regardless of care, all divers are subject to equipment failure and total loss of air supply.
In an environment as unforgiving as the underwater environment, a backup air supply is required for safety. Reserve underwater breathing systems do currently exist. They are typically comprised of an air supply which is separate from the main, or primary, air tank and which is held in reserve to be used either by the diver or by a second diver whose primary air supply is unavailable or exhausted.
One type of separate air supply, often referred to as a pony bottle, consists of a pressurized air tank, typically smaller in volume than the main air tank, with attached primary and secondary regulator. Because they duplicate some of the component parts of the primary system, such systems are relatively costly. Further, such reserve air tanks must also be refilled separately from the main tank or external source, thus requiring an extra step in the refilling procedure. In short, although they can be valuable, there is room for improvement in both the use and the cost of reserve air supplies over such systems.
The patent literature discloses several attempts to improve on these goals. For instance, Rinehart. U.S. Pat. No. 5,411,018 discloses an underwater breathing system having an oxygen tank smaller than the main air supply connected in parallel to the main air supply by a selector switch designed to control the ratio of oxygen/air mixture a diver consumes. This system, however, is intended for use in decreasing the severity of decompression sickness (the "bends") rather than as a reserve supply of breathable gas. Further, if utilized as a reserve supply, the system is likely to be even more difficult and/or time consuming to deploy than the pony bottle described above. Also complicated and difficult to use is the device disclosed in Lubitzsch, U.S. Pat. No. 4,951,660. This patent discloses a diver's rescue apparatus comprised of a fillable buoyancy element and a breathing bag, wherein the apparatus regulates the air mixture metered into the breathing bag
Almqvist et ai., U.S. Pat. No. 3,820,537 discloses an emergency self-contained underwater breathing apparatus (SCUBA) for supplementing a diver's normal gas supply including a helmet in combination with an auxiliary gas source capable of being supplied to the diver through a valve. In addition to the need for the helmet, the need for deployment disadvantages that apparatus.
None of the above cited references disclose a reserve air breathable gas supply system capable of receiving, air/oxygen flow from a main air tank, without allowing air/oxygen flow back into the main air tank. Nor do they disclose a "transparent" reserve air breathable gas supply system, i.e. a reserve system capable of supplying air/oxygen to a diver any time during a dive, without requiring deployment of that apparatus for use by the diver. Further, none of these prior patents discloses an apparatus with the additional convenience and safety features of structure which be used to fill a diver's buoyancy control device (BCD).
Therefore, it is a primary object of the present invention to provide a reserve air supply system capable of supplying air/oxygen to a diver without detaching the reserve air breathable gas supply system from the main air supply system.
It is a further object of the present invention to provide a reserve air supply system capable ot being replenished with air/oxygen concurrently with the replenishment of air or oxygen to the primary air supply system.
It is another object of the present invention to provide a reserve air breathable gas supply system that is transparent to the user, i.e. able to be filled without action on the part of the diver from the primary tank and then to provide air for breathing and to fill a diver's buoyancy control device (BCD), all without the need for operating valves, switching regulators, or other deployment.